Generally in assembling a computer casing, fasteners must be used for fixing of its surface panel, upper cover, base and other accessories. Such an assembly is time consuming, and insufficient tightness of fasteners would adversely affect the quality of finished products. Moreover, front and back side plates, on the base tend to be bent inwards or outwards upon application of external pressure, and hence a connecting board or strut is welded between them. It not only means additional labor, but also an obstacle to installation of the mother board. Hence, it is quite inconvenient to assemble a computer casing. In view of such defects, the inventor has created a structure of a computer casing which can have the base, upper cover and, surface panel assembled firmly with only a bolt, and without welding or other fasteners. The invention is characterized by:
(1) Installation of the surface panel and all switches, push buttons, sockets and other parts to the surface panel without fasteners of any nature (such as screw, adhesive, fastener, etc.).
(2) Use of only a bolt and internal connecting structure to fix the surface panel, base and upper cover together without welding or other fastening means.
(3) Forming of step edges by difference in time of pressing, which eventually eliminates the need for welding.